Instrument-board lamp



4 cause a b indi'ng glare, and the issuing light Patented Nov. 7, 1922.

STATES i ,43i4,956 "r OFFICE.

.PATE

THOMAS J. I KERWIN, 0F CHICAGO, ILL'INOIS.

INSTRUMENT-BOARD LAMP.

Application inea August V20,.-1921. serial-N0. 493,872

following to be a full, clear, and exact de scription of the invention, such as will enable others skilled in the art to which it ap-A pertains to make and use the-same.

My invention relates to means lfor controlling the direction in which light is emitted from a lamp, its general objects including those of providing simple and 'effective means whereby the light from a given lamp can normally be confined to beams issuing in predetermined ydirections and whereby light may also be afforded in vadditional,directions when desired.

More particularly, my invention relates to lamps adapted for use on instrument boards and the like, where a number of different` appliances require illumination, and aims to shield the direct rays of light from the eyes of the observer while adequately illuminating the appliances in connection with which. the lamp is used. For example, in automobile practice it --is customary to mount an oil indicator as well as'a battery ammeter and a speedometer on the dashboard of the vehiclev and it is importa-nt that the indicatying portions of such instruments should be adequately illuminated Aat night. It is also important that none of the rays of light from the lamp should issue directly toward the occu ants of the automobile s o as to should preferably be confined to the dials of the instrument so as not to create a glare eii'ect on a reduced scale when the driver of the vehicle is`looking elsewhere than on the instrument, as every such glare-producing eil'ect will reduce the readiness with which the driver can observe what is ahead of his vehicle. Dashboard lamps or switch-board lamps as heretofore constructed for this purpose have' commonly beenv provided with cowls hooding the lamps and each equipped withan opening on one 'side of ample size for permitting light to be emitted towards adjacent instruments while shielding the eyes of the driver from the direct rays of the lamp. In so doing, a considerable portion of the emitted light has been wasted on portionsof the dashboard or lswitchboard which do not ordinarily require illumina-1. tion and likewise wasted by being directed towards the floor of the car, thereby creating -a general brightness in front of the driver o f thevehicle which interferes somewhat with his visual acuity. Moreover, the cowls as commonly used for this purpose have Wasted a'consideiable proportion of the light x of the lamp by reflecting the same fromin' ner surfaces of the cowl into the interior of the latter, which is undesirable. y

. My 'invention aimsl to overcome these vari-` ous objections to the arrangements'heretofore 4in use byV providing a more efficient cowl or hood arrangement adapted to concentrate the emittedlight normally along beams issuing in predetermined directions,

and also aims to provide simple means whereby the extent and direction oli the emitted light may be increased at the will of the operatorso that the lamp mayalso illuminate the floor infront of his seat. Furthermore, my invention aims to provide an inexpensive construction adapted for such purposes and one which can readily be ernployed in connection with standard types of dashboard orswitchpboard lamps. Still further and more detailed objects will appear from the following specification and from the accompanying drawings, in which Fig. l is a fragmentary elevation 'of the dashboard of an automobile, showing a cowl 'lamp embodying my invention as employed in connection with three instruments mounted on the dashboard.

Fig. 2 is an elevation of the complete lamp socket employed in Fig. 1.

Fig. 3 is a central and longitudinal section through the same, taken along the correspondingly numbered line in Fig. 2'.

Fig. 4 is a horizontal section taken through Fig. 2 along the correspondingly numbered line of that ligurevv Fig. 5 vis an enlarged and 'fragmentary vertical section taken along the correspondingly numbered line of Fig. 2 and showing the means employed for normally latching the sliding collar in position.

Fig. 6 is a vertical section taken through the dashboard of thel automobile longitudinally of the latter, or along the line 6-6 of Fig. 1 but on a reduced scale, and showing how the lamp of my invention illuminates the floor of the car adjacent to the dashboard when the sliding collar is moved out of its normal position.

In the drawings, I am showingrthe dashboard 1 as carrying a lamp socket which has a threaded shank 2 extending throu h the dashiboard and'clamped to the latter ya nut 3 in the usual manner, and which has its forward casing portion 4 equipped with bayonet slots 5 for engaging the usual lateral projections on the base 6 of a lamp 7.

`Adjacent to its base, the socket also .has its 'shell enlarged to afford a cylindrical.

portion 8 slidably fitting an apertured cylinder 9 which forms a part of the cowl and which is latched tao the said cylinder bythe interlocking of corresponding indentations as shown at 10 in Fig. 3. 'The cylindrical casing portion 9 of the cowl is equipped with apertures 11, 12 and 1 3, all of which desirably have their axes substantially in the same plane4 transversely of the socket as that in .whlch the filament ofthe "lamp is disposed, it be. ing understood that lamps used forfthls purpose are standardized as to theirdi-y v mensions. The forward end ofV the' casing portion 9 is closedby an'endfportion' 14,

which may bearch'ed as shownv in the drawings to improve the ornamental' appearance and which is desirably made integral with the lateral casing portion 9.. The interior of the casing portion 9 is desirably of highly.

polished material so that it wil-l readily relect light striking against the same and will direct some of this'light outthrough'the said apertures, and the effective forward end of the casing is likewise desirably made of a highly polished reflecting material. This endward reflecting surface might be the interior of the dome 14, but for increased eiiiciency I preferably mount within the forward end ofthe casingportion 9 an auxiliary reflector l5 having a lateral flange 16 tightly fitting the bore ofthe said casing and having its main portion 17 in the form of a cone directing its tip towards the lamp:4 Thus arranged, it will be obvious from the dotted lines in Fig. 3 that thisv reiiector will redirect rays 'of light 'fromthe lamp` out through the said apertures while the cor- I therefore desirably indent the casing. 9

adjacent to and rearwardly of each of the apertures as shown in the drawings, so as to 'increase the extent to which light may issue I through each of these apertures toward the dashboard. v'Il liat to say, I )formthe cas*- ing` ofthe cowl so thatthe rearward edge of eachl-ight-emitting aperture vwill be curved Y inwardly vof-the casing. I( lonsequently, the indentations-20, 21and, 22' which arev respec-l tively adjacent'to the-"apertures 11, 12 and 13,' will be substantially in the form of scoops gradually sloping outward rearwardly of the socket, as "shown, in llong igtudinal section in Fig. A3. ,y

Thus arranged, it be obvious that by suitably locating thefapefrtures with respect to the relative locatioiiiof the lampand Of the instrumentswhich'are vto be illuminated, I can effectively-light the faces' of the latter without wasting `light on anyffother objects, and that the confining oftherays of llight to'suchoblique beams will leave the lamp effectivelyy screened .froml the eyes `of g the occupants f of the-1v automobile.

How-` ever, the light issuing through'theforward .halves'of the said apertures would pass be yond the dashboard or towards thelioor` of the lamp where it ordinarily would be undesirable. To avoid this, I normally close these 'forward'portions ofthe apertures by a collar 23 which ordinarily is in the position shown in Fig. 3. This collar desirably isl of such'a size 'as to be freely slid- .ablenon Athe casing 9, so that it can be slid out of the way as shown in Figs. 2 and 6, thereby permitting the floor in front of the drivers-seat and any objects adjacent to that floor to be lighted when desired. In practice, the casing portions between adjacent apertures may be rather narrow and can easily have slight humps 24 formed upon yieldingly'hold the latter in its normal position. I

With a cowl lamp thus constructed, it will be evidentA that by moving the collar 23 from'one position to" the other I can readily secureeither thel illumination of the instruments alone as shown in Fig., 1 and as indicated by dotted lines in Fig. 3, or the lightin of the floor of the car also when the driver wishes to enter the latter or wants to observe any items on or adjacent to the floor.

It will also beevident that the construction employed for-this purpose is exceedingly simple and inexpensive to manufacture, particularly as' the indenting of the casing adjacent tothe perforations permits me to increase the emission of light towards the board while employing a cylindricallysectioned die for punching each perforation. However, while I have illustrated and described my lamp-socket cowl in an embodiment including three apertures and one in which the sliding collar is latchedx in position by humps on'the casing between adjacent apertures, I do not wish to be limited to these or other details of the construction and arrangement thus disclosed, it being obvious the same to underhang the collar 23 so as to 2. A lamp socket equipped for holding an incandescent lamp, and a. hood carried by the socket and inclosing the lamp and l1aving on one side a plurality of light-emitting apertures all disposed in substantially alinement circumferentially of the hood and laterally opposite the source of light of the lamp, and a collar slidable on the hoodand normally closin the. portion of the apertures forward of the source of light.

3. A lamp socket equipped for holding an incandescent lamp, and a hood carried by the socket and inclosing the lamp and having on one side a plurality of light-emitting apertures all disposed in substantially alinement circumferentially of the hood and laterally opposite the source of light of the lamp, and a collar slidable' on the hood and normally closing the portion of the apertures forward of the source of light, the hood having a rigid formation limiting the forward sliding of the collar and yielding formation normally preventing a rearward slidin of the collar.

4. 1 lamp socket equipped for holding an incandescent lamp, and a hood carried by apertures all disposed in substantially alinement eircumferentially of the hood and laterally opposite the source of light of the lamp, and acollarslidable on the hood and normally closing the portion ofthe apertures forward of the source of light, the socket having a. portion between adjacent apertures formed for yieldingly latching the collar in itsinormal position.

5. A lamp socket equipped for holding a lamp with its source of lightvin predetermined position, and a` cowl hooding the lamp and having a plurality of light-emitting apertures spaced from each other circum# ferentially of the cowl, the side of the cowl being formed for increasing the emission of light rearwardly oblique of the socket, and movable means normally reventingr the emission of light through t 'e apertures in directions obliquely forward from the source 6. A lamp socket equipped for holding an incandescent lamp, and a hood carried by the socket and inclosing the lamp and having on one side a plurality of light-emitting apertures all disposed in substantially alinement circumferentially of the hood'and laterally opposite the source of light of the lamp, means normally covering the forward portionk of the apertures, and a reflector mounted within the hood and disposed for reflecting light from the lamp rearwardly oblique of the axis of lthe socket through the uncovered parts of the apertures.

Signed at Chicago, Illinois, August 15th,' 1921.

THOMAS J. KERWIN. 

